This invention relates generally to articulated tractors and more particularly concerns four-wheel-drive articulated tractors.
The trend in today's agricultural industry is to maximize the efficiency of each crop producing unit by increasing the size of the units. The larger units minimize the manual labor involved by making it possible to effectively utilize the larger horsepower tractors and their associated implements. As the available horsepower of a tractor increases, it becomes more economical and efficient to design, build and use a tractor that is articulated.
Although an articulated tractor is preferable, the size of the engine and the related power train for the high horsepower tractors has traditionally produced a high profile for the tractor. The high profile restricts the operator's visibility from the articulated tractor which has been a major factor in the elimination of these tractors from use in the planting, growing and harvesting of row crops such as corn, soy beans, and sun flowers.
For many years there has been extensive work down in the area of articulated tractor designs as exemplified by U.S. Pat. Nos. 1,957,917, 3,270,829 and 4,019,598. A study of these patents will show that the operator's visibility from the driver seat would severely limit his ability to maintain the tractor wheels in the spacing between the rows required by such crops. These patents clearly show that the engines and their related power trains are the causative factors in the high profile of the high horsepower articulated tractors.
The '598 and '829 patents are also exemplary of the extreme complexity of the drive trains of four-wheel-drive articulated tractors. The addition of the four-wheel-drive feature in an articulated tractor is designed to take full advantage of the high horsepower of the tractor's engine by maximizing the tractive effort of the tractor. Although the four-wheel-drive feature accomplishes its desired goal, these patents clearly show that it also contributes to the high profile of the tractor.
Accordingly, it is an object of the present invention to materially reduce if not substantially eliminate this particular visibility problem by providing an engine location and power train arrangement that minimizes their vertical space requirement.
Moreover, it is an object of the present invention to provide such a tractor with a power train that can maximize the tractor's tractive effort by utilizing a four-wheel-drive system.